The need to communicate is a regular aspect of many facets of modem society. Access to communication systems through which data is communicated is needed by many to provide and to receive conventional communication services. And, as advancements in communication technologies continue, new communication services, effectuated by improved communication systems, are likely to become available.
A communication system is formed of a set of communication stations including at least one sending station and at least one receiving station that are interconnected by way of a communication channel. Data sourced at a sending station is communicated upon a communication channel to a receiving station. If necessary, the sending station converts the data into a form to permit its communication upon the communication channel, and the receiving station converts the data received thereat into a form to permit the recovery of the informational content thereof.
A radio communication system is an exemplary type of communication system. The communication channel utilized upon which to communicate data between sending and receiving stations of a radio communication system is formed of a radio channel defined upon a radio air interface, a portion of the electromagnetic spectrum. Communication channels are otherwise generally defined in other communication systems upon conductive paths, i.e., wirelines, that interconnect the communication stations. By utilizing radio channels rather than channels formed upon wirelines, the wirelines that are otherwise required to interconnect the communication stations are obviated.
Because a wireline connection is not required to interconnect communication stations to communicate data therebetween, communication services are effectuable by way of a radio communication system when wireline connections interconnecting the locations at which the communication stations are positioned is not possible. Additionally, a radio communication system is available for implementation as a mobile communication system in which one or more of the communication stations is permitted mobility.
A cellular communication system is a mobile communication system. The networks of various cellular communication systems have been installed throughout significant portions of the populated areas of the world. Cellular communication systems are used to communicate telephonically to effectuate both voice and data communication services.
A user communicates by way of a cellular communication system through use of a mobile station. A mobile station is a radio transceiver that transceives data-containing communication signals with fixed-site transceivers that form parts of the network of the communication system. More generally, a mobile station, sometimes in conjunction with an additional device, is referred to as user equipment (UE). The fixed-site transceivers are referred to as base stations. The base stations are installed at spaced-apart locations throughout the geographical areas encompassed by the network of the communication system. The base stations each define a cell that represents a coverage area encompassed by the base station that defines the cell.
Communications by a mobile station, when positioned within a cell defined by a particular base station, generally communicates with that base station. Due to the inherent mobility of a mobile station, the mobile station might travel between cells defined by successive ones of the base stations. Continued communications with the mobile station are permitted through the effectuation of communication handoffs between successive ones of the base stations associated with the cells through which the mobile station passes.
First-installed cellular communication systems, referred to as first-generation systems, utilize analog communication techniques. So-called second-generation communication systems utilize digital communication techniques and provide limited data communication services. And, third-generation systems, are presently undergoing deployment. Third-generation systems provide for high-speed, variable rate data communication services.
An exemplary third-generation cellular communication system operates pursuant to the operating protocol set forth in a CDMA2000 operating specification. Packet-based communication services, and the operating protocols for effectuating such services, are set forth in the operating specification.
Various technology proposals by which to effectuate communication of packet data at high data rates in a CDMA2000 system have been proposed. The 1×EV-DV data communication service is one such proposal. Other data communication services are also proposed. Channels defined in a CDMA2000 system, as well as other code-division, multiple-access systems, are based upon codes by which communication data is coded. The code forms a spreading code that spreads data that is to be communicated from a low data rate to a spreading rate of 1.2288 Mcps. Codes assigned to communicate different concurrently-communicated data are orthogonal to one another to provide channel separation.
High data rate channels permit data to be communicated at high data rates and use proportionally more power for their transmission. Generally, this is achieved through the assignation of multiple orthogonal codes to a single communication session so that the throughput is the sum of all the related orthogonal channels assigned to the communication session. The number of orthogonal codes that are available by which to code data is limited. As the number of communication sessions increases, assignment of the codes must be controlled to allocate communication resources in a desired manner. Assignment of multiple orthogonal codes maps to so-called, 2×, 4×, 8×, or 16× supplemental channel assignments upon which high data rate communication services are effectuated.
When a cell is relatively unloaded, a communication allocation can be granted to a mobile station to effectuate the communication service at a high rate, such as through allocation of a 16× supplemental channel upon which to communicate the data to effectuate the communication service. When such a grant is made, an RLP (Radio Link Protocol) logical layer is permitted to send increased amounts of data on the radio air interface extending between the mobile station and the base station. And, accordingly, the TCP-layer (Transport Control Protocol-layer) window size is correspondingly sized.
However, in the event that loading conditions in the cell increase, i.e., the 16× supplemental channel assignment is reduced, e.g., to a 2× supplemental channel assignment. Reduced amount of data is communicated at the RLP layer. However, conventionally, the TCP layer is not made aware of the changed allocation. And, the TCP layer remains at a correspondingly large window size, and TCP-layer data is attempted to be communicated at the higher rate. TCP layer timeouts occur as a result. But, such timeouts are essentially spurious as the data is not actually sent out at the RLP layer. Analogous problems occur as a result of changing FER (Frame Error Rate) conditions that result in lower supplemental channel assignments. The spurious timeouts adversely affect the efficiency at which the data is communicated and the time period required to complete the communication service.
If a manner could be provided by which to reduce the occurrence of spurious timeouts, as a result of changes in loading conditions, improved communications would result.
It is in light of this background information related to communications in a packet radio communication system that the significant improvements of the present invention have evolved.